An electric motor may feature a rotor with permanent magnets and a stator, such as an interior permanent magnet (IPM) motor or an IPM synchronous motor. In accordance with certain prior art, an inverter or motor controller comprises semiconductor switches that support the provision of alternating current outputs for one or more phases of the electric motor. A short circuit, which appears across the output terminals of one semiconductor switch, may cause an asymmetric current to flow in the windings of an electric motor. The asymmetric current makes the motor susceptible to damage, such as demagnetization of one or more permanent magnets within the motor (e.g., or its rotor). Thus, there is a need for an improved method and controller for an electric motor with fault detection.